1. Field of the Invention
This invention relates generally to improvements to flush toilets to effect partial flushes of the toilet.
2. Description of the Prior Art
It is well known that in operation of the common flush toilet, the flapper valve which controls the flow of water through the drain at the bottom of the toilet may be utilized to effect a partial flush. If, after the flapper valve has been lifted from the valve seat encircling the drain, the flapper valve is returned to the valve seat after a set amount of water has flowed from the toilet tank reservoir into the toilet bowl, a partial flush has been accomplished.
Generally, a partial flush of the toilet utilizing one-half to one-third of the total water stored in the toilet tank is satisfactorily if one wishes only to flush away liquid wastes. Full flushes utilizing all the water contained in the toilet tank are necessary only when disposing of solid wastes. As a consequence, since liquid wastes are flushed from the toilet probably three out of four times that a toilet is used, great savings in water and costs are possible if partial flushes are utilized for disposal of liquid wastes rather than a full flush.
Flushing of a toilet utilizing a conventional flush mechanism is controlled by an operator manipulating a handle situated on the outside of the toilet tank. The operator presses down on the handle, initiating a rotation of the handle which in turn rotates upward a connected flush lever arm interiorly to the toilet tank, the resultant being a lifting of the distal end of the lever arm. To this distal end is attached a chain or string, the other end of which is attached to the flapper valve residing on the valve seat situated at the bottom of the tank. By lifting the flapper valve, presently done by rotating the flapper valve off the valve seat, water is permitted to flow through a drain centrally located in the valve seat and into the toilet bowl. When an operator fully depresses the flush handle, the flapper valve is raised up to a position sufficiently high above the valve seat so that the flapper valve becomes buoyant and does not return to the valve seat until all the water in the tank has drained.
An operator may effect a partial flush by depressing the flush handle a small amount rather than a full swing to thereby lift the lever arm a correspondingly small distance, whereupon the flapper valve will be lifted off the valve seat a corresponding small distance. In this scenario, the flapper valve will return to the valve seat when the operator releases the flush handle. The difficulty with this operation is that a person must be skilled in depressing the flush handles only a small portion of its total rotational travel as there is a tendency to push the full amount of travel.
Accordingly, a number of efforts have been devoted to providing mechanical means to acomplish partial flushes of a toilet wherein only a portion of the water stored in the toilet tank is used. One such device is shown in the 1989 United States Patent to Randall Toltzman, U.S. Pat. No. 4,864,665, entitled "DUAL FLUSH SYSTEM FOR TOILETS", the present inventor being the Assignee. The invention of this patent provides a pair of overlapping flush handles situated outside the toilet tank, one adapted to provide for a partial flush of the toilet and the second adapted to provide for a full flush. The partial flush handle operates through the flush lever arm interior to the tank to lift the flapper valve off the valve seat a short distance, in the order of a half an inch or so, to allow water to pass out of the toilet tank and into the toilet bowl. If the partial flush handle is depressed for about six seconds, sufficient water will have drained from the toilet tank into the toilet bowl to effect a partial flush. After six seconds or so has elapsed, the operator releases the partial flush handle and the flapper valve returns to its seated position upon the valve seat, thereby terminating the flow of water into the toilet bowl.
The flapper valve returns to the valve seat due to a number of factors, these factors believed to include the water pressure being exerted vertically down upon the flapper valve, and the suction of the water rushing past the sides of the cone shaped flapper valve into the centrally located drainway of the valve seat. When the flapper valve is no longer forcible held immediately above, but closely spaced to, the valve seat, the flapper valve will automatically return to the valve seat and terminate water flow.
When the flapper valve is raised to a position sufficiently high above the valve seat, the downward pressure of water upon the flapper valve and the suction upon the flapper valve is insufficient to overcome the inherent buoyancy of the flapper valve and the flapper valve rises to its highest most position (the flapper valve in most cases being pivoting on and off the seat valve). When the flapper valve has become buoyant, substantially all the water in the toilet tank flows into the toilet bowl. This is a full flush.
The invention of Toltzman works very well and does in fact accomplish both a partial flush and a full flush of the toilet (the full flush through the full flush handle). Yet, the instant inventor has found that operators are not usually willing to hold the partial flush lever down the required six seconds or so necessary to effect a partial flush. In most cases, the operator will push the partial flush lever down to begin the flush of the toilet, but will release the lever a second or two later. This allows the flush lever arm operably connected to the partial flush handle to move downward to its at-rest lowest position. Then the flapper valve connected to the flush lever arm is no longer suspended immediately above the valve seat and will return to the valve seat and terminate the flow of water. Unfortunately, insufficient water flows in that one to two second hold down period to effect a partial flush and thus the purpose of the invention is thwarped. Since the attempt of a partial flush has failed, the operator may then push the full flush handle which, also being operably connected to the flush lever arm, lifts the lever arm fully up, pulling the flapper valve off the valve seat high enough to become buoyant and a full flush results.
Another invention by which both a partial flush and a full flush may be effected in a toilet is shown by the patent to E. M. Gram, U.S. Pat. No. 2,744,261, issued May 8, 1956. In the invention of Gram, the outside toilet handle is directly attached to a cam inside the toilet tank. The cam operates upon one end of an independent flush lever arm by raising the second end of the lever arm to one set height when in the partial flush mode of operation, and then raising the second end to a higher level for the full flush mode. The above is accomplished by placing the fulcrum or pivot point of the independent flush lever arm generally central between its two ends. The first end is proximate the flush handle cam and the second end has attached to it the chain or string which connects to the flapper valve. Then, one lobe of the cam operates against the first end of the flush lever arm to depress the flush lever arm a relatively short distance which raises the second end of the flush lever arm a correspondingly short distance necessary for a partial flush. To accomplish this the flush handle is rotated up. For a full flush, the flush handle is rotated down whereupon a second larger lobe of the cam depresses the first end of the flush lever arm a greater distance, thus lifting the second end of the lever arm the necessary higher distance to raise the flapper sufficient to become buoyant.
The shortcoming of Gram's invention is that it does not conform to conventional methods of flushing toilets by pushing handle(s) down to accomodate both a partial flush and a full flush.
Accordingly, while the invention of Toltzman does adopt conventional flushing methods by pushing handles down to effect a partial and full flush, yet it also suffers from the shortcomings cited above.
Thus it becomes quite obvious that it would advantageous to have a device which assists an operator in accomplishing partial flushes of a toilet, whether or not the invention of Toltzman is installed on the toilet. Such device would have to hold up the flush lever arm at the proper height for the requisite time of a partial flush after the operator initially raised the lever arm, especially for those cases where the operator will not continue to hold the partial flush handle down. Such a device, however, must release the flush lever arm when sufficient water has passed into the toilet bowl to effect the partial flush so that the partial flush is terminated.